So I had the same situation happen to me yesterday, I was driving to work and all of a sudden my check engine light came on and the fuel gauge dropped to E with the fuel light on. Tried messing with it but the only thing that changed was the low fuel light went off and the fuel gauge appeared to be working. I wanted to make sure the fuel gauge was working so I stopped and put $20 in the tank, got back in the truck, started it up and the check engine light went away. Got home after work and cleared the code. My thought is that the fuel tank has pressure and if the fuel cap has a bad seal and isn't sealing properly, it might be throwing an invalid but relatable code. Maybe changing the fuel cap will work for some of you. If I'm wrong, then I'm wrong but it's worth a shot.